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c924098122
During config transactions on the PCIe bus an attempt to scan for a non-existent device can lead to a machine check exception with certain peripheral devices. In order to avoid crashing in such scenarios the instrumented versions of the config cycle read routines are introduced, so the exceptions fixups framework can gracefully recover. Signed-off-by: Grzegorz Bernacki <gjb@semihalf.com> Acked-by: Rafal Jaworowski <raj@semihalf.com>
98 lines
2.9 KiB
C
98 lines
2.9 KiB
C
/*
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* Copyright (C) 1999 Magnus Damm <kieraypc01.p.y.kie.era.ericsson.se>
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*
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* (C) Copyright 2000
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* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#include <common.h>
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/*
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* The exception table consists of pairs of addresses: the first is the
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* address of an instruction that is allowed to fault, and the second is
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* the address at which the program should continue. No registers are
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* modified, so it is entirely up to the continuation code to figure out
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* what to do.
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*
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* All the routines below use bits of fixup code that are out of line
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* with the main instruction path. This means when everything is well,
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* we don't even have to jump over them. Further, they do not intrude
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* on our cache or tlb entries.
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*/
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DECLARE_GLOBAL_DATA_PTR;
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struct exception_table_entry
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{
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unsigned long insn, fixup;
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};
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extern const struct exception_table_entry __start___ex_table[];
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extern const struct exception_table_entry __stop___ex_table[];
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static inline unsigned long
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search_one_table(const struct exception_table_entry *first,
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const struct exception_table_entry *last,
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unsigned long value)
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{
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long diff;
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if ((ulong) first > CFG_MONITOR_BASE) {
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/* exception occurs in FLASH, before u-boot relocation.
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* No relocation offset is needed.
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*/
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while (first <= last) {
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diff = first->insn - value;
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if (diff == 0)
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return first->fixup;
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first++;
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}
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} else {
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/* exception occurs in RAM, after u-boot relocation.
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* A relocation offset should be added.
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*/
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while (first <= last) {
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diff = (first->insn + gd->reloc_off) - value;
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if (diff == 0)
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return (first->fixup + gd->reloc_off);
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first++;
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}
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}
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return 0;
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}
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int ex_tab_message = 1;
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unsigned long
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search_exception_table(unsigned long addr)
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{
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unsigned long ret;
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/* There is only the kernel to search. */
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ret = search_one_table(__start___ex_table, __stop___ex_table-1, addr);
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/* if the serial port does not hang in exception, printf can be used */
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#if !defined(CFG_SERIAL_HANG_IN_EXCEPTION)
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if (ex_tab_message)
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debug("Bus Fault @ 0x%08lx, fixup 0x%08lx\n", addr, ret);
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#endif
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if (ret) return ret;
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return 0;
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}
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